Calling other people to communicate is natural to us nowadays. Even so, problems arise when we try to call somebody and the call is not answered. Usually the person we tried to contact checks his mobile phone later and notices our contact attempt. He will then normally call back to ask why he was called. This is not always what we wish. We do not always want the other person to call back to us, for example if we called the wrong person or we already got the information we wanted from somewhere else.
Currently the most natural way to let the other person know why we tried to call him is to send him an SMS (Short Message Service) message. With the current mobile phones, attaching messages to unanswered calls is cumbersome. The message is not combined with the call at the receiving end, because SMS messages cannot be associated with a particular call attempt. This can easily lead to unnecessary calls back to ask the reason for the call. Contact attempts are also shown in an unintuitive way; we are shown the number of missed calls and unread messages rather than who has tried to contact us. If a person has both called us and sent us an SMS message stating the reason for his call we may check the missed calls first and call the person before reading the message he has sent.